No, they are the iron heads that were on it from production...

Turns out, this happened when cruising down the highway at 60mph, about 2400rpm then out of nowhere, it happened and that one head's exhaust was making the classic "briggs & stratton" sound.

Engine builder and FE Ford expert still believe it is hydrolock from oil pressure.
Don't know what the pressure is because gauge does not work, working on getting a new one... they said oil filters without a bypass built in will cause oil pressure to rise...but doesn't the oil pump have a pressure release? It is a high volume pump in a 10 quart pan.

-CJP